Apparatus having an electronic component located on a surface of a package member with a space therebetween

ABSTRACT

An electronic component includes a package member; a via hole electrode extending through the package member and protruding from a first surface of the package member; an electronic component located on the first surface of the package member with a space located between the package member and the electronic component. The space between the electronic component and the first surface of the package member is provided by a protruding portion of the via hole electrode which extends from the surface of the package member and a joining member joining the electronic component with the via hole electrode.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus, such as a piezoelectricresonance device, having an electronic component located on a surface ofa package member with a space provided between the electronic componentand the package member.

2. Description of the Related Art

Some electronic devices require that a portion thereof does not contacta printed circuit board or substrate when mounted on the printed circuitboard or substrate or the like. For instance, in a piezoelectricresonator, a resonating section thereof must be arranged such that asufficient space between the resonating section and the printed circuitsubstrate is provided in order to prevent interference with theoscillation of the resonating section. In case of an exothermicelectronic component, it is necessary to mount the electronic componentsuch that a sufficient space between the printed circuit board orsubstrate and the component is provided in order to prevent heat fromconducting to the printed circuit board or substrate and other nearbyelements.

Various structures have been proposed for a piezoelectric resonator inorder to create such a space.

FIG. 17 is a partially cutaway section view showing one example of aprior art structure for mounting a piezoelectric resonator.

As seen in FIG. 17, electrode lands 52 a and 52 b are located on asubstrate 51. A piezoelectric resonator 53 is mounted in contact withthe electrode lands 52 a and 52 b. The piezoelectric resonator 53 has astructure in which a terminal electrode 53 b is located at one end of apiezoelectric plate 53 a and a terminal electrode 53 c is located at theother end. It is noted that a resonance electrode not shown is connectedto the terminal electrodes 53 b and 53 c.

The terminal electrodes 53 b and 53 c are connected to the electrodelands 52 a and 52 b via conductive adhesives 54 a and 54 b applied so asto have a certain thickness to prevent interference with the oscillationof a resonating section of the resonator 53.

That is, a gap 55 is created between the piezoelectric resonator 53 andan upper surface 51 a of the substrate 51 by increasing a thickness ofthe conductive adhesives 54 a and 54 b.

However, because the conductive adhesives 54 a and 54 b are liquid whenthey are applied, the conductive adhesive material is liable to flowalong the upper surface 51 a toward the center of the piezoelectricresonator 53 as shown by arrows A₁ and A₂ in FIG. 17. As a result, theresonating section is joined to the upper surface 51 a of the substrate51 via the conductive adhesive in the mounting structure, therebydegrading the resonating characteristics of the resonator 53. Inaddition, because the conductive adhesives 54 a, 54 b flow and extendalong the upper surface 51 a, the vertical dimension of the gap 55 isreduced and cannot be accurately or reliably provided.

Further, because the liquid conductive adhesives 54 a and 54 b arehardened after the application, the size and vertical dimension of thespace 55 varies. Often, the resonating section of the resonator 53contacts the upper surface 51 a of the substrate 51, thereby damagingthe resonating characteristics of the resonator 53.

In order to eliminate the aforementioned problems, there has beenproposed a mounting structure in which spacers 56 a and 56 b areinterposed between the terminal electrodes 53 b and 53 c and theelectrode lands 52 a and 52 b as shown in FIG. 18. The spacers 56 a and56 b are made of an electrically conductive material such as metal andare joined to the terminal electrodes 53 b and 53 c as well as theelectrode lands 52 a and 52 b via conductive adhesive or solder. A space55A is defined between the piezoelectric resonator 53 and the uppersurface 51 a of the substrate 51 by the vertical dimension of thespacers 56 a and 56 b.

However, this structure requires preparation of spacers 56 a and 56 bhaving a very accurate size and shape and also requires a difficult andtime-consuming process of applying the spacers 56 a and 56 b to mountthe piezoelectric resonator 53.

Meanwhile, there has been disclosed a small package structure forstoring a piezoelectric resonator and the like in Japanese PatentLaid-Open No. Hei. 5-83074. FIGS. 19a and 19 b are a partially cutawayplan view and a section view, respectively, showing the packagestructure of this prior art device.

The electronic component 61 includes an insulating substrate 62 and acap 63. A piezoelectric resonator 64 is stored within the package.Further, through hole electrodes 65 a-65 c are formed so as to extendthrough the substrate 62. The through hole electrodes 65 a-65 c areconstructed by creating through holes extending through the substrate 62and by applying an electrode material on the inner peripheral surfacesof the through holes. The inner peripheral surfaces of the through holesand the electrodes extend to the upper and lower surfaces so as to formflange-like portions.

The piezoelectric resonator 64 is joined to the through hole electrodes65 a-65 c via conductive adhesives 66 a-66 c. The conductive adhesives66 a-66 c are disposed in the through hole electrodes 65 a-65 c and arejoined to the flange-like portion at the upper surface of the substrate62 of the through hole electrodes 65 a-65 c.

It is thought that the electronic component 61 allows an area outside ofthe cap 63 to be reduced so that the device can be miniaturized becausethe piezoelectric resonator 64 is led to the outside via the throughhole electrodes 65 a-65 c.

However, because the piezoelectric resonator 64 is joined to the throughhole electrodes 65 a-65 c via the conductive adhesives 66 a-66 c in theelectronic component 61, oscillation of the resonating section isdamaged by the conductive adhesives 66 a-66 c which flow and spreadduring application thereof similar to the case of the mounting structure51 shown in FIG. 17. In addition, similar to the prior art device shownin FIG. 17, the prior art device in FIG. 19(b) experiences a problem ofnot being able to reliably provide an accurate vertical dimension of thegap between the resonator 64 and the substrate 62, which problem iscaused by the upper portions of the electrodes 65 a-65 c and theadhesives 66 a-66 c extending along and spreading out along the uppersurface of the substrate 62.

As described above, there have been problems with degrading resonancecharacteristics caused by the mounting structure 51 shown in FIG. 17 andby the electronic component 61 shown in FIG. 19 because the space havinga sufficient size or vertical dimension cannot be reliably provided dueto the fluidity and spreading of the conductive adhesive.

Further, the mounting structure shown in FIG. 18 has had problems withthe manufacturing and assembly process being complicated and costlybecause the spacers 56 a and 56 b have to be used.

SUMMARY OF THE INVENTION

To overcome the problems described above, the preferred embodiments ofthe present invention provide an apparatus including an electroniccomponent which is arranged and constructed to be fixed firmly to apackage member with a space being reliably provided therebetween and toallow the component to be easily manufactured.

The preferred embodiments of the present invention provide an electroniccomponent including a package member; a via hole electrode provided soas to extend through the package member and to protrude from a firstsurface of the package member; an electronic component located on thefirst surface of the package member with a space defined therebetween;the space between the electronic component and the first surface of thepackage member being determined by a protruding portion of the via holeelectrode extending from the surface of the package member; and ajoining member joining the electronic component with the via holeelectrode.

It is noted that the via hole electrode described in the presentspecification is intended to mean a solid electrode in which anelectrode material is filled completely within a through hole asdescribed later.

It is also noted that the via hole electrode does not extend along anupper or first surface of the substrate or package member as in theprior art. Instead, the via hole electrode extends vertically upwardlyfrom the first surface of the substrate or package.

Also, the via hole electrode is a completely solid member having arod-shaped configuration such that the rod-shaped member extends throughthe via hole and has an upper, rounded portion which extends verticallyfrom the upper surface of the substrate or package member in a directionthat is substantially perpendicular to the upper surface of thesubstrate or package member so as to support the resonator and toprovide an accurate vertical dimension of the gap between the resonatorand the package member.

With the structure of the preferred embodiments of the present inventionas described above, a space having a desired size or vertical dimensioncan be reliably provided between the electronic component and thepackage member. Accordingly, it becomes possible to provide anelectronic component such as a piezoelectric resonator which is mountedon the package member while reliably providing a sufficient spacetherebetween so that oscillation of the resonating section of theresonator is not hindered.

In addition, although the desired space in the prior art devices couldnot be obtained due to the fluidity and spreading of the adhesive duringapplication thereof in which the space between the electronic componentand the package member is created by the conductive adhesive, a spacehaving a sufficient vertical dimension is reliably provided in thepreferred embodiments of the present invention because of the shape andarrangement of the via hole electrodes and protruding portions of thevia hole electrodes. Further, because the preferred embodiments of thepresent invention do not require an extra member such as a spacer tocreate the space having the desired vertical dimension, the electroniccomponent of the preferred embodiments of the present invention is mucheasier and less expensive to manufacture. In addition, the rod-shaped,solid via hole electrode filling the via holes in the substrate in thepreferred embodiments of the present invention allow for significantlyless adhesive to be used as compared to the prior art devices in whichadhesive spread along the upper surface of the substrate and in somedevices, the adhesive spread into the via holes. Thus, even if theadhesive used in the preferred embodiments of the present inventionspreads along the upper surface of the substrate, the gap between theresonator and the substrate is accurately and reliably provided with anexact vertical dimension because of the rod-shaped, solid via holeelectrodes.

In the above described apparatus, the electronic component may be apiezoelectric resonator.

With the structure of the preferred embodiments of the presentinvention, an electronic component having excellent resonancecharacteristics is obtained.

In the above described electronic component, the via hole electrode maybe exposed at a second surface of the package member wherein the firstand the second surfaces of the package member are opposed to each other.

By the above-described structure, the electronic component at the uppersurface (the first surface) of the package member may be electricallyconnected with the lower surface (the second surface) of the packagemember by using the via hole electrodes. Accordingly, this arrangementallows the electronic component which can be readily mounted on thepackage member surface to be obtained by forming connecting electrodesand terminal electrodes on the lower surface of the package member.

In the above described electronic component, the package member maycomprise a ceramic substrate and a plurality of internal electrodes maybe provided in the package member so as to form at least one capacitor,and the via hole electrode may be electrically connected to thecapacitor.

With the above described structure, an electronic apparatus includes acomplex type package structure having a circuit in which the capacitorsare connected to the electronic component mounted on the package member.

In the above described electronic component, the package member maycomprise a ceramic substrate, a plurality of cutaways may be provided ona side of the ceramic substrate, and a plurality of external electrodesmay be provided in the plurality of cutaways.

With the above described structure, it becomes possible to form theexternal electrodes readily by using the same method as that used forforming the via hole electrodes and to provide a smaller electroniccomponent as compared to the external electrode using the through holeelectrodes.

According to another preferred embodiment of the present invention, amethod of forming the apparatus includes the steps of laminating aplurality of ceramic green sheets on a support film to obtain a ceramicgreen sheet laminate, forming through holes through the ceramic greensheet laminate at positions where via hole electrodes are to be located,applying conductive material into the through holes so as to fill thethrough holes and to be located on the upper surface of the ceramicgreen sheet laminate to form via hole electrodes, and sintering theceramic green sheet laminate to form a substrate and so as to formprotrusion portions of the via hole electrodes which protrude upwardfrom the upper surface of the substrate.

The via hole electrodes that are formed by the above process are solidand substantially rod-shaped. The via hole electrodes formed by theabove process fill the via holes with the solid, rod-shapedconfiguration. The protruding portions are formed because a coefficientof thermal contraction of the ceramics, during cooling after thesintering, is higher as compared to a coefficient of thermal contractionof the electrode material.

As a result of the protruding portions of the via hole electrodes, a gaphaving a sufficient size or vertical dimension can be reliably createdbelow the piezoelectric resonator and the substrate.

In a further preferred embodiment, the method includes the step ofsetting the coefficient of thermal contraction of the ceramics to behigher than the coefficient of thermal contraction of the electrodematerial filled in the through holes by about 1% to about 20%. With thisdesired range, the size of the gap is accurately and reliably achieved.

Other features and advantages of the present invention will becomeapparent from the following description of the present invention whichrefers to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal section view showing an electronic componentaccording to a first preferred embodiment of the present invention.

FIG. 2 is a transverse section view of the electronic component shown inFIG. 1 along a line A—A in FIG. 1.

FIG. 3 is a transverse section view illustrating an electronic componentaccording to a second preferred embodiment of the present invention.

FIG. 4 is a plan view of the electronic component shown in FIG. 3.

FIG. 5a is a partially cutaway section view illustrating a through holeelectrode.

FIG. 5b is a partially cutaway section view for illustrating a via holeelectrode.

FIG. 6a is a schematic plan view illustrating a positional relationshipbetween an external electrode and an electronic component having athrough hole electrode.

FIG. 6b is a schematic plan view illustrating a positional relationshipbetween an external electrode and an electronic component having a viahole electrode.

FIG. 7 is a transverse section view for explaining a modified example ofthe first preferred embodiment.

FIG. 8a is a longitudinal section view illustrating another modifiedexample of the first preferred embodiment.

FIG. 8b is a transverse section view illustrating another modifiedexample of the first preferred embodiment.

FIG. 9a is a longitudinal section view illustrating another modifiedexample of the first preferred embodiment.

FIG. 9b is a transverse section view for explaining another modifiedexample of the first preferred embodiment.

FIG. 10 is a transverse section view for explaining a modified exampleshown in FIG. 9b.

FIG. 11 is an exploded perspective view for explaining an electroniccomponent according a third preferred embodiment of the presentinvention.

FIG. 12 is a perspective view showing an appearance of the electroniccomponent of the third preferred embodiment.

FIG. 13 is a longitudinal section view of the third preferredembodiment.

FIG. 14 is a section view along a line D—D in FIG. 13.

FIG. 15 is a section view corresponding to a portion along a line E—E inFIG. 13.

FIG. 16a is a section view for illustrating a via hole electrode havingan elliptic plan shape is elliptic.

FIG. 16b is a plan view illustrating a via hole electrode having anelliptic plan shape.

FIG. 17 is a section view illustrating a prior art electronic component.

FIG. 18 is a partially cutaway section view illustrating another exampleof a prior art electronic component.

FIG. 19a is a partially cutaway plan view illustrating still anotherexample of a prior art electronic component.

FIG. 19b is a partially cutaway section view illustrating anotherexample of a prior art electronic component.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIGS. 1 and 2 are frontal and side section views showing an electroniccomponent according to a first preferred embodiment of the presentinvention.

In the electronic component 1 shown in FIG. 1, a piezoelectric resonator3 is mounted on a substrate 2 in a package arrangement. Further, a cap 4preferably made of a metal is fixed to the substrate 2 so as to surroundthe piezoelectric resonator 3. The cap 4 is arranged so as to create aninternal space in which the piezoelectric resonator 3 is stored. Theinternal space inside of the cap 4 is defined by the cap 4 having asubstantially U-shape which is arranged so that the open portion thereoffaces downward and is fixed to the upper surface of the substrate 2 viaadhesive (not shown).

The substrate 2 is preferably made of insulating ceramics such asalumina. Via hole electrodes 5 and 6 are formed to extend through thesubstrate 2.

As seen in FIG. 1, the via hole electrodes preferably comprise solid,rod-shaped members which are arranged to penetrate through the substrate2 such that protruding portions at the upper ends of the via holeelectrodes 5, 6 protrude upward from the upper surface 2 a of thesubstrate 2. It is important to note that the protruding portions of thevia hole electrodes 5, 6 do not extend along the upper surface of thesubstrate 2 but instead extend vertically from the upper surface of thesubstrate 2 in a direction that is substantially perpendicular to theupper surface of the substrate 2. Lower surfaces of the via holeelectrodes 5 and 6 are exposed at a lower surface 2 b of the substrate 2and are connected to terminal electrodes 7 a and 7 b disposed on thelower surface 2 b of the substrate 2.

The piezoelectric resonator 3 is constructed by using a piezoelectricmember 3 a formed of piezoelectric ceramics such as titanatepiezoelectric ceramics. The piezoelectric member 3 a is polarized in thethickness direction and has an internal electrode 3 b. Further,electrodes 3 c and 3 d are located on the upper and lower surfaces ofthe piezoelectric member 3 a so that the electrodes 3 c, 3 d overlapwith the internal electrode 3 b at an approximately central region ofthe piezoelectric member 3 a. The internal electrode 3 b is located atone end of the piezoelectric resonator 3 and is electrically connectedto a terminal electrode 3 e which extends to the bottom surface of thepiezoelectric member 3 a. The electrodes 3 c and 3 d are electricallyconnected to each other by a terminal electrode 3 f located at the otherend of the piezoelectric member 3 a.

The piezoelectric resonator 3 is preferably an energy trap piezoelectricresonator utilizing a thickness longitudinal oscillation mode and isdriven when AC voltage is applied between the terminal electrodes 3 eand 3 f. The piezoelectric resonator 3 is located on the portion of thevia hole electrodes 5 and 6 which protrudes from the upper surface 2 aof the substrate 2 and is fixed thereto by conductive adhesives 8 a and8 b on the substrate 2.

Because the upper ends of the via hole electrodes 5 and 6 protrudeupward from the upper surface 2 a of the substrate 2 as described above,a space 9 having a size or vertical dimension that is sufficient toprevent interference with the resonance of a resonating section isreliably provided between the lower surface of the piezoelectricresonator 3 and the upper surface 2 a of the substrate 2. That is, thepresent preferred embodiment is characterized in that the via holeelectrodes 5 and 6 are provided so as to extend through the substrate 2,the upper ends of the via hole electrodes 5 and 6 protrude upward fromthe upper surface 2 a and the piezoelectric resonator 3 is arranged suchthat a space having a vertical dimension corresponding to the protrusionof the via hole electrodes 5 and 6 is defined between the substrate 2and the resonator 3.

The via hole electrodes 5 and 6 are preferably constructed by filling anelectrode material in the through holes created through the substrate 2.The upper protrusion of the via hole electrodes 5 and 6 is preferablycreated by the following fabrication method.

That is, before obtaining the substrate 2, a plurality of ceramic greensheets are laminated on a support film to obtain a ceramic green sheetlaminate. Next, through holes are created through the ceramic greensheet laminate at the portions where the via hole electrodes 5 and 6 areto be located. Next, a squeegee step is performed from above the ceramicgreen sheet laminate supported by the support film to deposit the liquidor slurry conductive material such as conductive paste into the throughholes. Because the through holes are filled with the conductive materialvia the squeegee, the upper surface of the electrode material filled inthe through holes is shared with the upper surface of the ceramic greensheet laminate.

However, when the ceramic green sheet laminate described above issintered to obtain the substrate 2, the protrusion portions whichprotrude upward from the upper surface 2 a of the substrate 2 arecreated above the via hole electrodes 5 and 6 as shown in FIG. 1 becausea coefficient of thermal contraction of the ceramics, during coolingafter the sintering, is higher as compared to a coefficient of thermalcontraction of the electrode material, i.e. the coefficient of thermalcontraction of the electrode material is smaller.

It has been discovered that the space 9 having a sufficient size orvertical dimension can be reliably created below the piezoelectricresonator 3 by setting the coefficient of thermal contraction of theceramics to be higher than the coefficient of thermal contraction of theelectrode material filled in the through holes by about 1% to about 20%.It is noted that when the difference of the coefficients of thermalcontraction described above is less than about 1%, the height of theprotrusion portion of the via hole electrodes 5 and 6 becomesinsufficient to reliably provide a space 9 that has a size or verticaldimension which allows for unhindered vibration of the resonator 3. Whenthe difference in coefficients of thermal contraction described aboveexceeds about 20%, the protrusion portion of the via hole electrodes 5and 6 becomes too high, thus causing the piezoelectric resonator 3 tobecome unstable which makes it difficult to stably and accuratelyperform adhering steps using the conductive adhesives 8 a and 8 b andnegatively affecting the resonator characteristics. It also makes itdifficult to reduce the size and vertical height of the electroniccomponent 1.

FIGS. 3 and 4 are section and plan views for explaining a secondpreferred embodiment of the present invention.

FIG. 3 corresponds to FIG. 2 shown for the first preferred embodiment.

An electronic component 10 of the second preferred embodiment ischaracterized in that electronic components 11 a, 11 b, 11 c and 11 dwhich are preferably formed by the same method described above have viahole electrodes 5 and 6 formed on the sides of the substrate 2. Theother features are preferably the same as the electronic component 1 ofthe first preferred embodiment.

That is, the electronic components 11 a, 11 b, 11 c and 11 d arepreferably formed by completely filling the electrode material withinpreferably substantially semicircular (in plan view) cutaways 2 ethrough 2 h formed in side surfaces 2 c and 2 d of the substrate 2. Thatis, the electrode material composing the external electrodes 11 athrough 11 d is applied so as to almost fill the cutaways 2 e through 2h and so as not to reach the upper and lower surfaces of the substrate2.

The external electrodes 11 a through 11 d are preferably formed at thesame time that the via hole electrodes 5 and 6 are formed. That is, amother substrate for obtaining a plurality of substrates 2 is prepared,substantially circular through holes having a size (in plan view) thatis about twice that of the cutaways 2 e through 2 h are created at thepositions corresponding to the cutaways 2 e through 2 h on the mothersubstrate and at the same time, through holes for forming the via holeelectrodes 5 and 6 are created.

After that, a liquid conductive member such as a conductive paste isfilled in each through hole via a squeegee and the mother ceramic greensheet laminate is cut in units of each substrate. Thus, the ceramicgreen sheet laminate in which the electrode material is filled in thecutaways 2 e through 2 h is obtained. When the ceramic green sheetlaminate is sintered and then cooled, the electrode material filled inthe cutaways 2 e through 2 h are baked and the external electrodes 11 athrough 11 d are formed as the substrate 2 is sintered and the via holeelectrodes 5 and 6 are baked.

Accordingly, the external electrodes 11 a-11 d are formed through thesame process along with the via hole electrodes 5 and 6. Also, theelectronic components 11 c and 11 d are formed so as to be electricallyconnected with a terminal electrode 7 b located at the lower surface ofthe substrate 2. Accordingly, during surface-mounting of the component10 on a printed circuit board or substrate or the like, the electroniccomponent 10 may be joined to electrode lands of the printed circuitboard or substrate or the like by connecting the external electrodes 11a-11 d via soldering or the like. At this time, while a soldering filletis formed to join the external electrodes 11 a-11 d with the electrodelands, the state of connection between the external electrodes 11 a-11 dand the electrode lands may be readily confirmed visually from outsideof the component.

The electronic component 10 of the present preferred embodiment allowsthe state of connection when mounted on the printed circuit substrate orthe like to be readily confirmed visually. Also, the size of thesubstrate is significantly reduced as compared to the prior artelectronic component in which external electrodes are formed on the sideof the substrate in the same manner with through hole electrodes (FIG.19) by forming the external electrodes 11 a-11 d as described above.This will be explained with reference to FIGS. 5a, 5 b, 6 a and 6 b.

FIG. 5a is a partially cutaway section view showing a prior art throughhole electrode. The through hole electrode 61 is formed by creating athrough hole 62 a through a substrate 62 and by applying an electrodematerial so as to extend to an inner peripheral portion and to upper andlower surfaces of the through hole 62.

However, the via hole electrode is formed by creating a through hole 12a through a mother substrate 12 and by filling an electrode material 13within the through hole 12 a as shown in FIG. 5b.

Accordingly, when the through hole electrode 61 is formed and is cut atan alternate dotted line B in FIG. 5a to form a substantiallysemi-circular (in plan view) external electrode in the stage of themother ceramic laminate, a flange portion 61 a of the through holeelectrode 61 is formed so as to extend to the inside more than a cutaway63 at the upper and lower surfaces of the substrate 62 as shown in FIG.6a.

When the external electrode 13A is formed as shown in FIG. 6b by cuttingalong the center of the via hole electrode 13, the external electrode13A will not extend to the inside more than the cutaway 12 a.Accordingly, when a distance between an inner edge of the externalelectrode 61A shown in FIG. 6a and an electronic component C mounted onthe substrate 62 is made equal to a distance between an inner edge ofthe external electrode 13A in FIG. 6b and the electronic component Cmounted on the substrate 12, the size of the substrate 12 which does nothave the flange portion 61 a may be reduced as compared to the substrate62 by an amount equal to that portion. That is, the use of the externalelectrode 13A formed in the same manner along with the via holeelectrode allows the substrate to be miniaturized as compared to theexternal electrode 61A formed in the same manner as the through holeelectrode.

Accordingly, although the external electrodes 11 a-11 d are formed inthe electronic component 10 shown in FIGS. 3 and 4, it allows thesubstrate 2 to be miniaturized or the electronic component 10 to beminiaturized as compared to the case of using the prior art externalelectrode formed in the same manner with the through hole electrode.

Although the external electrodes 11 c and 11 d which are formed on theside of the substrate 2 have been formed so as to protrude upwardly fromthe upper surface of the substrate 2 in the electronic component 10shown in FIG. 3, external electrodes 11 e and 11 f which extend to anintermediate vertical position may be formed as shown in FIG. 7 insteadof the external electrodes 11 c and 11 d. The state of connection of theelectrode lands on the printed circuit substrate and the externalelectrodes 11 e and 11 f may be readily confirmed visually when theelectronic component 14 is mounted on the printed circuit substrate orthe like also when the external electrodes 11 e and 11 f are formed.Further, the substrate 2 may be miniaturized in the same manner asdescribed above with reference to the second preferred embodiment.

The external electrodes 11 e and 11 f may be formed as follows. A firstplurality of ceramic green sheets which corresponds to a ceramic layeron which the external electrodes 11 e and 11 f are to be formed arelaminated on a support film to obtain a ceramic green sheet laminate bylaminating the ceramic green sheets. At this time, through holes arecreated through each ceramic green sheet at a location where theexternal electrodes 11 e and 11 f are to be formed and a conductivemember is injected to each through hole in advance. Then, the pluralityof ceramic substrates are laminated while aligning the correspondingthrough holes to which the conductive member has been injected. Next, asecond plurality of ceramic green sheets corresponding to the ceramiclayer which is located above the upper end of the external electrodes 11e and 11 f are laminated. Through holes are created through the secondceramic green sheets at the position where the via hole electrodes 5 and6 are to be formed and a conductive member is filled in the throughholes in advance of the lamination process.

Then, the substrate 2 on which the external electrodes 11 e and 11 f areformed may be obtained by cutting the mother ceramic green sheetlaminate in units of each individual substrate and by sintering thelaminate.

FIGS. 8a and 8 b are longitudinal and transverse section views showinganother modified example of the electronic component 1 of the firstpreferred embodiment.

Although the cap 4 has been fixed on the substrate 2 in the electroniccomponent 1, the structure of the package for storing the electroniccomponent may be changed as desired according to preferred embodimentsof the present invention.

For example, a structure in which a substantially rectangular frame 22is combined with a cap 23 may be used instead of the cap 4 as in theelectronic component 21 shown in FIGS. 8a and 8 b. Here, thesubstantially rectangular frame 22 preferably made of insulatingceramics such as alumina is fixed to the upper surface of the ceramicsubstrate by using insulating adhesive and the cap 23 made of metal orplastic is fixed on the frame 22. The other components are the same asthose of the electronic component 1 shown in FIG. 1, so that the sameparts are denoted by the same reference numerals and repetitiveexplanation thereof will be omitted here.

It is also possible to construct a package by using a frame 24 which isthicker than the piezoelectric resonator 3 and by fixing a plate-likelid 25 on the upper surface of the frame 24 as shown in FIGS. 9a and 9b. An electronic component 26 shown in FIGS. 9a and 9 b is constructedin the same manner with as electronic component 1 except that the frame24 and the plate-like lid 25 are used instead of the cap 4 (FIG. 1).

It is noted that the material composing the frame 24 and the cap 25 isnot specifically limited. Further, the frame may be made of the samematerial with the substrate or may be sintered at the same time with thesubstrate.

It is also possible to construct the component so as to be able toconfirm the presence and physical characteristics of a fillet created bythe solder or the like visually from the outside when mounted on aprinted circuit substrate or the like by forming external electrodes 11c and 11 d on the side of the ceramic substrate 2 like an electroniccomponent 27 shown in a transverse section view of FIG. 10 in the samemanner with the electronic component 10 shown in FIG. 3.

An electronic component according to a third preferred embodiment of thepresent invention will be explained with reference to FIGS. 11 through15.

In the present preferred embodiment, the package preferably includes asubstantially square package member 31 having an opening 31 a at theupper part thereof and a plate-like lid 32 fixed so as to close theopening 31 as shown in an exploded perspective view of FIG. 11. Apiezoelectric resonator 3 is stored within the package. Thepiezoelectric resonator 3 is constructed in the same manner as thepiezoelectric resonator 3 shown in FIG. 1.

Accordingly, the electronic component 33 obtained in the presentpreferred embodiment has almost a substantially rectangularparallelepiped shape as shown in FIG. 12. FIG. 13 shows a longitudinalsection view of the electronic component 33. FIG. 14 shows a transversesection view along an alternate dotted line D—D in FIG. 13 and FIG. 15shows a section corresponding to a part along an alternate dotted lineE—E in FIG. 13.

The package member 31 is preferably made of dielectric ceramics such asalumina. Via hole electrodes 35, 36 and 40 are formed through thepackage member 31 so as to penetrate through the ceramic layer. The viahole electrodes 35 and 36 protrude upward from an inner bottom 31 b ofthe package member 31. Accordingly, the piezoelectric resonator 3 placedon the package member 31 is disposed so as to float from the innerbottom 31 b while leaving a space A having a predetermined size orvertical dimension. Further, the piezoelectric resonator 3 is connectedwith the via hole electrodes 35 and 36 by conductive adhesives 37 a and37 b.

Meanwhile, the package member 31 has steps 31 c and 31 d at one pair ofsides facing to each other. As shown in FIG. 14, the via hole electrode36 is extended to the vertical position where the steps 31 c and 31 dare created. A lower edge of the via hole electrode 36 is electricallyconnected with a connecting electrode 38 which is formed at the verticalposition where the steps 31 c and 31 d are created.

A plurality of internal electrodes for composing capacitors are formedbetween the inner bottom 31 b of the package member 31 and the step 31d. That is, a plurality of internal electrodes 39 a connected to the viahole electrodes 35 and 36 and a plurality of internal electrodes 39 bconnected to the via hole electrode 40 are formed. The internalelectrodes 39 a and the internal electrodes 39 b are disposed so as tooverlap each other via the ceramic layers.

The via hole electrode 40 is connected to the uppermost one of theinternal electrodes 39 b and the upper edge thereof does not reach theinner bottom 31 b as is apparent from FIG. 13. Meanwhile, the lower edgeof the via hole electrode 40 extends to the vertical position where thesteps 31 c and 31 d are formed and is electrically connected with aconnecting electrode 41.

External electrodes 42 a-42 c are formed at the part below the steps 31c and 31 d of the package member 31 on the sides thereof (see FIG. 11).The external electrodes 42 through 42 c are formed on the pair of sidesfacing each other.

As shown in FIG. 14, the external electrodes 42 c are electricallyconnected with a connecting electrode 38 and consequently, areelectrically connected with the via hole electrode 36. Meanwhile, theexternal electrodes 42 b and 42 b are connected with the connectingelectrode 41 and consequently, are electrically connected with a viahole electrode 40 as shown in FIG. 15.

Therefore, a circuit structure in which the piezoelectric resonator andtwo capacitors are connected between the external electrodes 42 athrough 42 c may be realized in the electronic component 33 of thepresent preferred embodiment.

As described above, the electronic component of the present preferredembodiment of the present invention permits the capacitors including theplurality of internal electrodes to be constructed within the packagemember. In this case, a desired circuit may be structured byelectrically connecting the plurality of internal electrodes with thevia hole electrodes.

Because the electronic component 33 of the present preferred embodimentshas the circuit structure in which the piezoelectric resonator and twocapacitors are connected as described above, it may be suitably used asa piezoelectric resonator for example.

Although the via hole electrode having a substantially circulartransverse section has been shown in the above-mentioned preferredembodiment, the sectional profile of the via hole electrode is notlimited to a substantially circular shape in the present invention. Forinstance, the section of a via hole electrode 42 may be substantiallyelliptical as shown in FIGS. 16a and 16 b. In such a case, an electroniccomponent may be stably located via member 42 a protruding from apackage member 43. The sectional profile of the via hole electrode isnot limited to the substantially elliptical shape and may assume anyshape such as a substantially rectangular or substantially square shape.

Further, it is possible to support an electronic component more stablyby disposing a plurality of via hole electrodes in close proximity.

While the invention has been particularly shown and described withreference to preferred embodiments thereof, it will be understood bythose skilled in the art that the forgoing and other changes in form anddetails may be made therein without departing from the spirit of theinvention.

What is claimed is:
 1. An apparatus, comprising: a substrate made ofceramic material; a plurality of via holes provided in the substrate; atleast one via hole electrode provided in at least one of the pluralityof through holes and comprising a solid member made of a conductiveelectrode material and which completely fills the at least one of thethrough holes and extends through the at least one through hole in thesubstrate so as to protrude by a protruding amount from a first surfaceof the substrate; an electronic component located on the first surfaceof the substrate with a space defined between the first surface of thesubstrate and the electronic component, the space between the electroniccomponent and the first surface of the substrate being determined by theprotruding amount of the via hole electrode protruding from the surfaceof the substrate, the via hole electrode being in contact with the firstsurface of the electronic component; and a conductive adhesiveelectrically connecting the electronic component with the at least onevia hole electrode; wherein the conductive adhesive extends between thesubstrate and the electronic component, is in contact with theprotruding amount of the via hole electrode, the substrate and theelectronic component, and substantially surrounds the protruding amountof the via hole electrode protruding from the surface of the substrate;and wherein the coefficient of thermal contraction of the ceramicmaterial of the substrate is higher than the coefficient of thermalcontraction of the conductive electrode material filled in the at leastone of the through holes by about 1% to about 20%.
 2. The electroniccomponent according to claim 1, further comprising a plurality of viahole electrodes each provided in a respective one of the plurality ofthrough holes and each comprising a solid member which completely fillsthe respective one of the through holes and extends through therespective one of the through holes in the substrate so as to protrudeby a protruding amount from a first surface of the substrate.
 3. Theelectronic component according to claim 1, further comprising a terminalelectrode connected to the at least one via hole electrode at a secondsurface of the substrate which is opposite to the first surface of thesubstrate.
 4. The electronic component according to claim 3, wherein theterminal electrode is arranged to be substantially perpendicular to theat least one via hole electrode.
 5. The electronic component accordingto claim 1, wherein the electronic component is a piezoelectricresonator.
 6. The electronic component according to claim 1, wherein theat least one via hole electrode is exposed at a second surface of thesubstrate; and the first and the second surfaces of the substrate areopposite to each other.
 7. The electronic component according to claim1, wherein a plurality of internal electrodes are provided in thesubstrate to define at least one capacitor, and the least one via holeelectrode is electrically connected to the capacitor.
 8. The electroniccomponent according to claim 1, wherein a plurality of cutaways areprovided on a side of the ceramic substrate, and a plurality of externalelectrodes are provided in the plurality of cutaways.
 9. The electroniccomponent according to claim 1, wherein the joining member comprises anadhesive material located between the electronic component and the atleast one via hole electrode.
 10. The electronic component according toclaim 1, wherein the at least one via hole electrode comprises asubstantially rod-shaped member.
 11. The electronic component accordingto claim 1, wherein the at least one via hole electrode includes aprotruding portion which protrudes from the via hole above the firstsurface of the substrate in a direction that is substantiallyperpendicular to the first surface of the substrate.
 12. The electroniccomponent according to claim 1, wherein the at least one via holeelectrode includes a protruding portion which does not extend along thefirst surface of the substrate.